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ANT203Y1 Lecture Notes - Steropodon, Furongian, Ossicles

Course Code
Maryam Nargolwalla

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Macroevolution Oct, 04, 2011
Linnaean Classification
Taxonomy :dymanics- now organisms relate, reasons behind
Classification of humans
Kingdom: Animalia (animals)
Phylum: Chordata (chordates)
Class: Mammalia (mammals)
Order: Primates (primates)
Family: Hominidae (hominids)
Genus: Homo (humans)
Species: Homo
*italicize species name
o First letter of genus capitalised (Homo)
o Species begins with lowercase letter (Homo sapiens)
o Genus and species are both italicised (Homo sapiens)
o Genus name may be abbreviated (H. sapiens)
Kingdom: Animalia
Motile; means they can move around
Heterotrophic ; they are depended on other organisms as a food
Precambrian Era(~610Ma)
Ex. Stromatlite and trilobite
Phylum: Chordata
Notochord and nerve cord: flexible joint and rod
Gill slits
Muscles, respiration
Cambrian (~540Ma)
*evolved in the Palaeozoic period
*ex. Amphioxus, lets us alot about vertibe origins and how these early
chordate evolves
Subphylum: Vertebrata
Jawless and bony fishes, sharks and rays, amphibians, reptiles,
mammals, birds
Segmental spinal column
Developed brain, paired sensory structures (balance, sight,
Heads and tails
Closed circulatory system: have heart and blood v vessels
Upper Cambrian (~510Ma)
Ex. Agnathans- Agna= jaw hans=less/ lampreys & hagfis, they have
fins gills 2 chambered hearts
Class: Mammalia
Sweat glands (including mammary glands) produce milk
Auditory ossicles = 3 bones in ear
Neocortex: are that gives us higher functions in the brain / in
human =language
↑ ontogeny: growth and dev. Animals have it in both
Viviparous: give birth to live youngs
Specialized dentition/heterodont: different kinds of teeths
(3insisors :1:4:3molars)
Endothermic: keep body at regulated temperature dispite whats
going on outside
Jurassic (~199-145Ma)
Mammal Origins
-Dimetrodon: mammal like reptile more mammal thn reptile
-Steropodon: mammals that layed eggs
-Sinodelphis: first evidence of pouched mammals
-Eomai: first placental mammal
Order: Primates
*originated about 65 mya right after the extinction of dinosaurs
Lemurs, lorises, tarsiers, monkeys, apes, humans
Generalized structure (e.g., pentadactyly : 5fingers and toes, ↑
ontogeny, dentition, limb structure:allows to move around in a
number of way
-mammals have specialized dentition
Binocular: front of the skull= over lapping fields of vision ,
stereoscopic vision= seeing in 3d depth perception
Opposable thumbs, grasping hands/feet, nails instead of claws
Ex, carries traits of order primates= Plesiadapis, Smilodectes
Homology ( Richard Owen 1848)
Similarity in fine structure or development of body part due to
common ancestry
Homologous characters
o Primitive (plesiomorphic)
o Derived (apomorphic)
o Shared-derived (synapomorphic)
Similarity due to common function, not descent
Homoplasy; refers to phycial similarities, occur as response living in
same environment
Ex. Wings of bird and bat
Phylogenetic Systematics and Cladistics
o patterns of relatedness→classification
o character analysis
o homologies (shared-derived)
caldas groups of organisms that share a common ancestor
o PS includes time, ancestor-descent relationships
o C includes fossil and living species together – clades →
monophyletic groups